GB2320085A

GB2320085A - A sub-calibre projectile

Info

Publication number: GB2320085A
Application number: GB9724276A
Authority: GB
Inventors: Bernhard Bisping; Jurgen Kolodzey; Wolfgang Stein; Alfons Sackarndt
Original assignee: Rheinmetall Industrie AG
Current assignee: Rheinmetall Industrie AG
Priority date: 1996-12-06
Filing date: 1997-11-17
Publication date: 1998-06-10
Anticipated expiration: 2017-11-17
Also published as: CH693009A5; DE19650741C2; US5905228A; FR2757625B1; GB2320085B; GB9724276D0; DE19650741A1; FR2757625A1

Abstract

A sub-calibre projectile comprises a penetrator (2), a discarding sabot (3) surrounding the penetrator, and a plastic hood (5) mounted on the front of the sabot (3) and conically tapering in the direction of the nose (4) of the penetrator. To ensure a simple and economical connection between the plastic hood (5) and the sabot (3) the material selected for the hood (5) is a thermoplastic and the plastic hood (5) is secured to the sabot (3) using an ultrasonic welding or deforming process. The plastic hood (5) is peripherally heated in at least two zones (11) by ultrasonic spot welding and deformed into a groove-shaped recess (9) in the sabot wall in such a way that the resulting inwardly directed protuberances (12) interlock with the groove-shaped recess (9).

Description

1 TITLE 2320085 Sub-calibre Projectile This invention relates to a method

for manufacturing a sub-calibre projectile and to a sub-calibre projectile produced by such method.

Sub-calibre projectiles which are to be fired from automatic weapons comprise a penetrator, a discarding sabot surrounding the penetrator and a plastic hood mounted on the front of the sabot and tapering towards the nose of the penetrator. The plastic hood, also termed a feeder hood, is designed both to facilitate the automatic feed of the relevant ammunition into the cartridge case and to protect the nose of the penetrator and the sabot. The provision of groove-shaped pre-set rupturing points extending in the longitudinal direction of the projectile is intended to ensure, particularly in the case of spin-stabilised projectiles, the defined disintegration of the feeder hood on passage through, and after emergence from the barrel and immediately in front of the muzzle.

Thus the corresponding segments of the hood will separate to the side as the projectile leaves the barrel.

With known projectiles the plastic hood is secured to the front zone of the sabot, by a snap connection, an adhesive or a screw connection. These known types of connection suffer from a number of drawbacks.

If a snap connection is applied after the injection moulding of the plastic hood, for example, the said hood requires relatively expensive mechanical finishing operation. Furthermore, with a snap connection, the 2 1 plastic hood is already overstretched at the assembly stage and is thus liable to break along the pre-set rupturing grooves. If the feeder hood comprises a highly ductile material, so that it will not break in this manner, the pre-set rupturing points will not suddenly rupture in front of the muzzle of the barrel in the required manner and the accuracy of the projectile on the target is thus seriously reduced. The strength of such hoods when subject to the feeding action thus regularly fails short of the requirements.

Adhesive connections are likewise relatively expensive to produce. A further problem arising with a connection of this kind is the fact that owing to the widely varying security in the adhesion between the hood and the sabot, the hood segments do not become detached uniformly. This has adverse effects on the accuracy of the penetrator.

Finally, screw connections as well as being expensive to produce generally cause a reduction in the cross section of the hood and sabot.

One object of this invention is to provide a method for the simplified and economic connection of a plastic hood with a sabot, ensuring that the projectile will be satisfactorily and reliably fed into position and with good accuracy when fired from automatic weapons. This invention also provides a sub-calibre projectile manufactured by the method.

According to this invention there is provided a method for the manufacture of a sub-calibre projectile comprising a penetrator, a discarding sabot embracing the penetrator, and a plastic hood mounted on the front of the sabot and conically tapering in the direction of the nose of the penetrator, wherein..

3 the sabot is provided in a front zone with at least one outward facing groove-shaped recess on the outer periphery of the sabot, the material of the hood comprises a thermoplastic and the hood is mounted on the said front zone of the sabot in such a way that the groove- shaped recess is covered by the hood,and the plastic hood is heated in at least two places using an ultrasonic process and deformed into the groove- shaped recess of the sabot in such a way that the resulting inwardly directed deformed zones of the plastic hood interlock with the groove- shaped recess.

This invention also provides a sub-calibre projectile having a penetrator, a discarding sabot surrounding the penetrator and a plastic hood positioned on the front of the sabot and conically tapering towards the nose of the penetrator, the sabot having in a front zone at least one outwardly facing peripheral groove-shaped recess, the plastic hood covering the front zone of the sabot and the plastic hood being deformed on the periphery in at least two zones into the groove-shaped recess of 20 the sabot by a heating process, in such a way that inwardly directed protuberances are produced in the plastic hood which interlock with the groove-shaped recess.

This invention is thus primarily based on the principle of using a thermoplastic material for the hood and securing the plastic hood to the sabot by an ultrasonic welding or deforming process. For this purpose 4 the plastic hood is peripherally heated or caused to flow in at least two zones by an ultrasonic welding or deforming process. For this purpose the plastic hood is peripherally heated or caused to flow in at least two zones by an ultrasonic process and deformed into a groove-shaped recess of the sabot in such a way that the resulting inwardly directed protuberance zones of the plastic hood interlock with the groove-shaped recess of the sabot.

The feeder hood therefore no longer requires any mechanical finishing after the injection moulding, even in the internal zone by which contact is made with the sabot. This type of feeder hood and its connection with the sabot make it possible to dispense With the otherwise necessary annular securing band in the front sabot, holding the segments of the latter together, for example during transport.

A reliable connection between sabot and plastic hood can be very simply obtained if the recess is provided in the form of an annular groove.

This invention is further described and illustrated with reference to examples and the drawings showing preferred embodiments.

In the drawings:- Figure 1 shows a side view, partly in section, of a projectile according to this invention, with a feeder hood, and Figure 2 shows a longitudinal section of the front zone and to an enlarged scale, of the projectile illustrated in Figure 1.

In the drawings, Figure 1 shows a sub-calibre projectile 1 comprising a penetrator 2, a sabot 3 made up of a number of discarding segments and a thermoplastic feeder hood 5 connected to the front of the sabot 3 and tapering in the direction of the nose 4 of the penetrator (Figure 2). the feeder hood 5 has four pre-set rupturing grooves 7 distributed evenly around the periphery and extending in the direction of the longitudinal axis 6 of the projectile 1.

The feeder hood 5 is mounted on a front zone (Figure 2) of the sabot 3, this zone of the said sabot 3 having a reduced external diameter in relation to the ammunition calibre. The sabot 3 is also provided in the front zone 8 with an annular groove 9 which extends from the periphery 10 of the front zone 8 of the sabot 3 into the wall of the said sabot and is covered over the plastic feeder hood 5.

Between each two adjacent pre-set rupturing grooves 7 two discrete zones 11 of the plastic hood 5 (Figure 1) are provided with inwardly directed protuberances 12 which interlock with the groove 9 of the sabot 3 (Figure 2), securing the said plastic hood 5 in position in relation to the sabot 3.

According to this invention the protuberances 12 are not inserted into the ring groove 9, until after the plastic hood 5 has been mounted onto the front zone 8 of the sabot 3 by ultrasonic sealing, so that there is no risk that the part of the plastic hood 5 which faces towards the sabot 3 will be overstretched, as occurs in the case of a snap connection.

The invention is naturally not confined to the example described in the foregoing. the number of pre-set rupturing grooves 7 for instance, may be greater or smaller than four. The number of separate zones 11 between each two adjacent pre-set rupturing grooves may also be greater or smaller than two.

6

Claims

1. A method for the manufacture of a sub-calibre projectile comprising a penetrator, a discarding sabot embracing the penetrator, and a plastic 0,5 hood mounted on the front of the sabot and conically tapering in the direction of the nose of the penetrator, wherein: the sabot is provided in a front zone with at least one outward facing groove-shaped recess on the outer periphery of the sabot, the material of the hood comprises a thermoplastic and the hood is mounted on the said front zone of the sabot in such a way that the groove-shaped recess is covered by the hood,and the p!astic hood is heated in at least two places using an ultrasonic process and deformed into the groove-shaped recess of the sabot in such a way that the resulting inwardly directed deformed zones of the plastic hood interlock with the groove-shaped recess.

2. Method in accordance with Claim 1, wherein the groove-shaped recess comprises an annular peripheral groove-

3. Method in accordance with Claim 1 or 2, wherein a plastic hood having a number of pre-set rupturing grooves evenly distributed over the 2.5 periphery and extending in the direction of the longitudinal axis of the 7 projectile has at least two protuberances between each two adjacent preset rupturing grooves and deformed into the groove-shaped recess of the sabot.

4_ A sub-calibre projectile having a penetrator, a discarding sabot surrounding the penetrator and a plastic hood positioned on the front of the sabot and conically tapering towards the nose of the penetrator, the sabot having in a front zone at least one outwardly facing peripheral groove-shaped recess, the plastic hood covering the front zone of the sabot and the plastic hood being deformed on the periphery in at least two zones into the groove-shaped recess of the sabot by a heating process, in such a way that inwardly directed protuberances are produced in the plastic hood which interlock with the groove-shaped recess.

5. A sub-calibre projectile and method of making same as described herein and exemplified with reference to the drawings.